Atosiban is a peptide analog of oxytocin that antagonizes the human oxytocin receptor (Ki = 81 nM).1 It also binds the vasopressin V1a receptor (Ki = 3.5 nM).1 Because of its effects on the oxytocin receptor, atosiban has tocolytic actions in the acute phase of imminent preterm birth.2,3,4
1.Cirillo, R., Tos, E.G., Schwarz, M.K., et al.Pharmacology of (2S,4Z)-N-[(2S)-2-hydroxy-2-phenylethyl]-4-(methoxyimino) -1-[(2'-methyl[1,1'-biphenyl]-4-yl)carbonyl]-2-pyrrolidinecarboxamide, a new potent and selective nonpeptide antagonist of the oxytocin receptorJ.Pharmacol. Exp. Ther.306(1)253-261(2003) 2.Lamont, R.F.The development and introduction of anti-oxytocic tocolyticsB. J. O. G.110 (Suppl 20)108-112(2003) 3.Moutquin, J.M., Sherman, D., Cohen, H., et al.Double-blind, randomized, controlled trial of atosiban and ritodrine in the treatment of preterm labor: a multicenter effectiveness and safety studyAm. J. Obstet. Gynecol.182(5)1191-1199(2000) 4.Romero, R., Sibai, B.M., Sanchez-Ramos, L., et al.An oxytocin receptor antagonist (atosiban) in the treatment of preterm labor: A randomized, double-blind, placebo-controlled trial with tocolytic rescueAm. J. Obstet. Gynecol.182(5)1173-1183(2000)